A pair of knickers that once belonged to Queen Victoria – Britain’s longest-reigning monarch, who died at age 81 in 1901 – have sold for a record-breaking $16,300 at auction.

The large white cotton pants – featuring a 45-inch waist – caused a serious bidding frenzy when they went up for bid at Chippenham Auction House on Saturday.

“We were flabbergasted!” auctioneer Richard Edmonds tells PEOPLE, adding, “As far as we can tell, it’s the highest price ever paid for Victoria’s knickers, and we are delighted.”

Including fees, the bidder paid $19,233 for the roomy royal undergarment, which is considerably more than previous records. However, there was one distinctive feature on these seemingly plain white undies that gave them the edge.

“On these particular knickers, there is a chevron section which is where they were taken up slightly as Queen Victoria got older and essentially she shrunk in stature,” explains Edmonds, who sold the garment on behalf of Yesterday’s World Museum in Sussex.

The “make do and mend” mentality favored by so many royals today (Princess Anne in particular!) meant that the garment could be pinned to a specific decade.

“That element got the collectors really excited, because you can then date them quite specifically to the last 10 years of her life,” explains the auctioneer.

Stamped with the monarch’s initials “VR” (short for “Victoria Regina”) and a number which related to a specific batch of clothing, the garment was in excellent condition, thanks to being kept in tissue paper in a temperature-controlled store room.

The winning bidder, a female English collector who also bought a number of other items including royal clothing and a set of replica crown jewels, has chosen to remain anonymous.

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